A NEW ‘baby’ potato variety is proving a big hit with a leading Scottish growers’ group.

Members of Montrose-based co-operative, Grampian Growers, are using Gemson’s unique tuber growth habit to add value to their potato crop.

Being able to control tuber size and hit the spec’ needed to target particular markets is critical for achieving the premiums that go with seed and baby potatoes.

The co-op has recently re-focussed its attentions away from traditional varieties such as Maris Piper, Maris Peer and King Edward, utilising recent advances in breeding and taking advantage of the fact that its base is near to the bespoke breeding programme facilitated by the James Hutton Institute, in Dundee.

It now has exclusive use of the variety Gemson, which is giving members increased returns through a greater proportion of the desirable and growing under 45mm crop.

Grampian Growers’ general manager, Sandy McGowan, said that though the group specialised in seed production, Gemson was very much a dual-purpose variety – 35% of which is destined for the ware market and packed locally in Scotland, with some product going to Ireland.

“It’s fast becoming a premium baby variety in the UK,” he said. “Grampian Growers have planted 185 ha of certified seed this year and because of its flexibility, we plan for around 35% of the crop at under 45mm to be sold for packing and the remaining 65% retained for seed. That’s budgeting on a gross yield of 45-50t/ha.”

Out of 6000 tonnes of Gemson grown by the group last year, less than 100 tonnes ended up in the less desirable upper greater than 55mm range.

“It’s purely a numbers game,” he continued. “Gemson has the ability to produce 20-35 tubers/plant, compared to Peer at 12-15 tubers/plant for the same gross yield.

“That means a way higher proportion of the valuable under 45mm fraction, where we accurately control the size management. Peer is more of a 50:50 ratio, whereas Gemson can reliably perform at 65:35.”

The genetic advantages that Gemson bring to that market are one thing, but in order for the variety to deliver commercially, crop management is crucial and none more so than at burn off. Growers are encouraged to accurately flail the tops, once the tuber size ratio is optimum and then desiccate rapidly after 48 hours using Spotlight Plus to ensure that growth is halted and quality preserved by reducing the chance of infection by tuber blight.

“We encourage our growers to be as precise as possible when flailing,” added Mr McGowan. “Generally, remaining stems should be about 20-30cm in length before we apply the Spotlight Plus. If conditions don’t allow for that, then we might use diquat, followed by the Spotlight Plus, but we’ve noticed a significant increase in size where that is the case.

“The more accurate the flailing, then the less work there is for the carfentrazone-ethyl to do.”

This key product can be used on all salad, ware and seed potato varieties and its rapid mode of action on stems, ensures that regrowth is not an issue.

Where tuber size is critical, then fine tuning of the crop can be achieved and maximum yield realised. Importantly, there is no aquatic buffer zone requirement and a seven-day harvest interval gives further flexibility to growers.

“With Gemson, we have the perfect variety to be able to achieve maximum output,” said Mr McGowan. “As a direct replacement for Peer, the potential for the variety is huge.

“When we apply the correct techniques, we can manage conditions in a way that realises that potential and one of the most important factors in the equation is using Spotlight Plus. Without its ability to rapidly desiccate the stems, manage tuber size and preserve quality, we’d be looking at a far less valuable crop.”